Keyfork arrangement



July 7, 1964 c. w. ANDERSEN` ETAL 3,139,780

KEYFORK ARRANGEMENT Filed April 4, 1961 2 Sheets-Sheet 1 July 7, 1964 c. w. ANDERSEN ETAL 3,139,780

KEYFORK ARRANGEMENT Cllmm i 17]: @Zw/@g IHIIHHHII'HIIIllllllm Filed April 4, 1961 United States Patent O 3,139,730 KEYFORK ARRANGEWIENT. Cliiiord W. Andersen and Phillip l. Roehrig, De Kalb, lll., assignors to The Wurlitzer Company, Chicago, lll., a corporation of Ohio Filed Apr. 4, 1961, Ser. No. 100,599 Claims. (Cl. 84-240) This invention relates generallykto piano actions and especially to arragements for connecting a piano action to its operating key.

In the past, piano actions have been connected to their 4respective operating keys in compliance with a variety of schemes. The connections in drop-type actions have been commonly made, for example, by providing a bore in the rear of the key. After the free end of a lifter rod has been passed through this bore, a nut or similar element is secured to the end of the rod over the top of the key. More recently, this scheme has been supplanted by assembling a fork to the end of the key and by securing a rubber grommet to the end of the lifter rod, the rod being releasably secured to the key by inserting the grommet in a keyhole-shaped notch openingfrom the end of the fork. This latter arrangement, while aording a certain facility in assembly and disassembly of the lifter rod and Vthe key, has proved susceptible of incurring objectionable play or looseness in the connection. j

Accordingly, an important objectof the presentinvention is to provide an arrangement which aggressively interconnects a drop-type piano action and its operating key.

A more general object of the invention is to provide a new and improved connection for a piano action and its operating key lever.

Another object of the invention is to provide a keyfork arrangement that insures positive'transmission of key lever motion to a cooperating piano action.

Additional objects and features of the invention pertain to the particular structure and arrangements whereby the above objects are attained. n

A structure in accord with the invention includes a manually operable key lever fulcrumed intermediate its end; an endwise reciprocable link; a connecting element of tough material on the link adjacent the rear end of the key lever restrained against longitudinal movement relative to the link, the connecting element having a constricted portion defining an endless groove perpendicular to the link; a fork rigid with and projecting from the rear end of the key lever, the fork including generally parallel disposed arms having straight confronting edges spaced apart to pass the constricted portion of the connecting element freely; and barb means on the arms aggressively engaging the sidewalls of the groove.

The invention, both to its structure and mode of operation, will be better understood by reference to the following disclosure and drawings forming a part thereof, wherein: y,

FIG. 1 is a side-elevational view in partial cross-section showing a piano action and its operating key connected in accordance with the invention; n

FIG. 2 is an enlarged plan view of the keyfork used in the piano action of FIG. 1;

FIG. 3 is a side elevationaliview of the keyfork ofy FIG. 8 is a perspective view of a modiiied screw usedy in mounting the attaching grommet to the lifter rod;

ICS

FIG. 9 is a perspective view of a further modified screw;

FIG. 10 is a perspective View of yet another modified screw;

FIG. 11 is a perspective View of still another modied screw; and

FIG. l2 is an enlarged view of a modified grommet and its attaching screw, the grommet being shown in section and the screw being shown in elevation. n

Referring now in detail to the drawings, specifically to FIG. l, a piano structure indicated generally by the numeral 20 is shown to include a front panel 22, akeybed 24 and frame 26. In accordance with conventional practice, a vertical backplate 28 is secured to the frame 26, and piano strings 30 are suitably stretched from the backplate 23. A balance rail, not shown, is mounted on a horizontal panel 32 that is superposed on the keybed 24 whereby to support an appropriate number of piano keys 34. While each of the keys 34 is fulcrumed on a balance rail pin to pivot about the balance rail, a guide pin 36 operates in a bore formed in the key to direct the outer end of the key. Guide pin 36 is surrounded by a'felt washer 38 which serves as a downstop@ A keybed felt 40 is appropriately secured to the end of panel 32 in order to support the keys 34 in their rest position.

Manual depression of the outer end of a key 34 is arranged to result in the striking of a corresponding string 30 through a piano action indicated generally by the numeral 42. The piano action 42 is mounted in the piano structure by means of suitable number of action brackets 44. Each of the brackets 44 is fastened to the backplate 28 by a screw 46 and a tubular, action spacer 48. A mainrail 59, a spring rail 52 and a hammer rail 54 eX- tend through the piano structure to be aiiixed to each of the action brackets 44 for purposes of supporting the individual action members.

The piano action 42 is of the type commonly referred to as an inverted-sticker action or a drop action; and is well'known, each hammer 56 of such an action includes a butt SSwhich is pivotally mounted to the mainrail 50 by means of a butt flange 60. The hammer 56 is urged to strike the corresponding string 3i) by means of a jack 62 which is pivotally mounted to a whip 64 by means of a jack flange 66. The'whip 64, in turn, is pivotally mounted to mainrail 50 by a whip ilange 68; and an abstract, sticker or lifter rod is pivotally mounted to the whip 64 by a pin 72. Depression of the key 34 causes an endwise reciprocation of the lifter rod 70 for actuating the jack 62. y n

A screw element 74 threadedly engages the free end of lifter rod 70, rod 70 being preferably fabricated from wood or other similar material. Accordingly, screw ele ment 74 is capable of readily entering a hole bored axially in the lifter rod 70., Alternatively, the screw element 74 can be urged into progressive engagement with the rod 70 directly. A connecting el-ement 76 fashioned in the `shape of a grommet is assembled to the shank of screw element 74 to be positioned directly beneath a screwhead `78. Advantageously, the screw element 74 is provided with annular knurls which are adapted to restrain the connecting elements 76 against longitudinal movement 'v relative to the lifter rod 7 0.

A keyfork 82 is rigidly mounted to the end of piano key 34 as by having a tongue portion 84 driven directly into portion defining a groove for receiving the arms of the Vkeyfork in a manner which will be described more fully hereinafter. The tongue 84 of the keyfork is coated piano key 34.

The remaining elements of the piano action 42 which are illustrated in FIG. l comprise no part of the present invention. Accordingly, these elements are not described in detail herein.

Turning now to FIGS. 2 and 3 for a more detailed description of the construction of keyfork 82, in addition to the tongue 84, the keyfork will be seen to include a pair of generally parallel disposed arms 86 which have straight confronting edges SS and which are spaced apart laterally in order to pass the constricted portion of the connecting element 76 in a free manner. The arms 86 define a generally U-shaped notch 98 opening away from the tongue 84; and in accordance with an important feature of the invention, barb means are fashioned in the edges 88.

These barb means advantageously take the form of points or spurs 92 and 94 which project toward the tongue 84 at an oblique angle relative to the principle plane of the keyfork 82. This is particularly well shown in FIG. 3. As will be recognized, raising the spurs 92 and 94 from the edges 88 transversely of the arms S6 avoids constriction of the notch 90. Furthermore, arranging the spurs 92 and 94 on opposite sides of the edges 88 cooperates in defining a keyfork having two planes of symmetry, such an arrangement being useful for manufacturing purposes.

The inside corners of the tips of the arms 36 are desirably cut or otherwise suitably formed to define laring lips 96 for reasons to be brought out hereinafter.

With reference to FIG. 4, the connecting element 76 will be seen to include a constricted portion dening an endless, circumferential groove 98 that is disposed perpendicularly to the axis of screw 74. On both sides of the groove 9S, the connecting element 76 incorporates a flange 100. The groove 98 has a cylindrical floor 102 and sidewalls 104, the sidewalls 104 being dened by the flanges 100.

Because of the particular construction of the cooperating keyfork 82, a wide range of relatively tough materials have proved suitable for the connecting element '76. Natural rubber and other elastomeric materials are useful, but the material for the connecting element 76 need not be as yieldable as rubber. Accordingly, such materials as vulcanized libre, cork, felt, molded resinous plastics such as nylon, soft metals such as copper, lead aluminum and their alloys, and various resin laminates of linen, paper and the like have also proved suitable.

In accordance with the showing of FIGS. 4 and 5, the lips 96 lead the constricted portion of the element 76 into the notch 90 in assembly of the element 76 to the keyfork 82. It will be noted that the central body or core of the connecting element 76 which is bounded by the cylindrical lioor 102 of the groove possesses a diameter which is approximately equal to the spacing between the edges of the arms 86. Accordingly no appreciable compressive forces are imposed on the element 76 in assembly, thus permitting substantial latitude in the selection of the material for the construction of the connecting element 76.

As the element 76 and the keyfork 82 are urged together, the sloping sides of the spurs 92 and 94 readily lead the anges 100 of the element 76 over the sharp tips of the spurs. Eventually, the floor 102 of the groove 98 will engage the bottom of the notch 9i) as is shown in FIGS. 6 and 7. In this position, the spurs 92 and 94 will be in aggressive engagement with the sidewalls 104 of the groove 98 making extraction of the element 76 from the keyfork 82 difficult. The highly positive engagement thus incurred effectively prevents movement of the screw 74 in the direction of the plane of keyfork 82. Lost motion and the resultant undesirable noise which would otherwise be associated with such movement is thus eliminated.

The particular embodiment of the invention which has been thus far shown and described does not delineate the 4 scope of the invention. Many modiiications may be made. For example and with reference to FIGS. S-ll inclusive, modified forms of the screw element are shown. In FIG. 8, a screw element is shown having a hexagonal head 112. r1`he head 112 is provided with diametrically arranged slots 114 adapted to cooperate with the blade of a screwdriver for use in emergency situations. Under ordinary circumstances, provision of the hexagonal head 112 permits adjustment in the penetration of screw element 110 into the lifter rod using a socket-type tool or nut driver. By the use of such an implement, no downward pressure is necessary to maintain engagement of the tool with the screw head. By eliminating such downward pressure axially of the screw element, corresponding pressure on the felt 40 is avoided during regulation of the piano action. Eicient and exact regulation of the piano action is thus facilitated.

The screw element 110 also includes an annular enlargement 116 formed on the shank of the screw element spaced beneath the head 112, the enlargement 116 specically taking the form of an inverted conical element. The enlargement 116 is spaced from the head 112 by a distance approximating the axial dimension of the connecting element 76 in order to restrain the connecting ellement against longitudinal movement on the shank of the screw element.

In FIG. 9, a further modified screw element 128 is shown having a hexagonal head 112 with diametric slots 114 similarly to the correspondingly designated elements of the screw element 110. The screw element 121i includes an annular enlargement 126 which specilically comprises a disc or washer-like element. The enlargement 126 is spaced from the head 112 appropriately to confine the connecting element much in the manner of enlargement 116.

FIGS. 10 and 1l also disclose modified forms of the screw element. In FIG. 10, the screw element 130 incorporates an annular enlargement 136 which is provided in the form of a spherical ring whereas the screw element 140 of FIG. ll is provided with an enlargement 146 taking the form of a flattened section or upstanding disc.

Turning now to FIG. l2, a screw element will be seen provided with a slotted, round head 152 and a straight-walled shank 154. The screw element 150 cooperates with a modied connecting element 156 which is provided with a circumferential groove 158 and spaced apart llanges 168. The connecting element 156 is additionally fashioned with a recess 162 which matably receives the head 152 of screw element 150. Gripping elements 164 are provided at the mouth of recess 162 for yieldably passing the head 152 into the recess and for restraining the head against subsequent longitudinal movement relative to the screw element 150. The gripping element 164 advantageously takes the form of an annular ring or a multiplicity of radial tabs. In order to facilitate a passage of the head 152 over the gripping means 164, the connecting element 156 is desirably fashioned from an elastomeric material.

The foregoing specic embodiments should be considered as illustrative only. Various changes in structure will, no doubt, occur to those skilled in the art; and such changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

l. In a piano action, the combination comprising: a manually operable key lever fulcrumed intermediate its ends; an endwise reciprocable link; a connecting element on said link adjacent the rear end of said key lever restrained against longitudinal movement relative to said link, said element having a constricted portion dening an endless circumferential groove disposed transversely of said link; a fork rigid with and projecting from the rear end of said key lever, said fork including generally parallel disposed arms having straight confronting edges spaced apart to pass the constricted portion of said element freely; and barb means on said arms aggressively engaging the sidewalls of said groove.

2. In a piano action, the combination comprising: a manually operable key lever fulcrumed intermediate its ends; an endwise reciprocable link; a connecting element of tough material on said link adjacent the rear end of said key lever restrained against longitudinal movement relative to said link, said element having a constricted portion defining an endless circumferential groove disposed transversely of said link; a fork rigid with and projecting from the rear end of said key lever, said fork including general parallel disposed arms having straight confronting edges spaced apart toi pass the; constricted portion of said element freely; and means on said arms aggressively engaging the sidewalls of said groove, including obliquely extending points facing generally toward said key lever.

3. The combination according to claim 2 wherein said points face from opposite sides of each of said arms.

4. In a piano action, the combination comprising: a manually operable key lever fulcrumed intermediate its ends; an endwise reciprocable link; a connecting element of tough material on said link adjacent the rear end of said key lever restrained against longitudinal movement relative to said link, said element having a constricted portion and parallel flanges on either side thereof defining an endless circumferential groove substantially perpendicular to said link; a fork rigid with and projecting from the rear end of said key lever, said fork including generally parallel disposed arms having straight confronting edges spaced apart to pass the constricted portion of said element freely, confronting edges of said arms engaging the floor of said groove; and means on said arms aggressively engaging the sidewalls of said groove, including obliquely extending points facing generally toward said key lever.

5. In a piano action, the combination comprising: a manually operable key lever fulcrumed intermediate its ends; an endwise reciprocable link having a head on one end; a connecting element of tough, elastomeric material on said link adjacent the rear end of said key lever, said element being fashioned with a recess matably receiving said head and having gripping means at the mouth of said recess for yieldably passing said head into said recess and restraining said head against longitudinal movement relative to said link, said element having a constricted portion defining an endless circumferential groove disposed transversely of said link; a fork rigid with and projecting from the rear end of said key lever, said fork including arms spaced apart to pass the constricted portion of said element freely; and barb means on said arms aggressively engaging the sidewalls of said groove.

6. In a piano action, the combination comprising: a manually operable key lever fulcrumed intermediate its ends; an endwise reciprocable link; a connecting element on said link adjacent the rear end of said key lever, said element having a constricted portion defining an endless circumferential groove substantially perpendicular to said link; means on said link xing said element against longitudinal movement, including a head on the free end of said link abutting said element and an enlargement on said link beneath said element; a fork rigid with and projecting from the rear end of said key lever, said fork including arms having straight confronting edges spaced apart to pass the constricted portion of said element freely; and barb means on said arms aggressively engaging the sidewalls of said groove.

7. The combination according to claim 6 wherein said enlargement comprises a transversely disposed disc.

8. The combination according to claim 6 wherein said enlargement comprises an inverted conical element.

9. The combination according to claim 6 wherein said enlargement comprises a spherical ring.

10. The combination according to claim 6 wherein said enlargement comprises an upstanding disc.

References Cited in the file of this patent UNITED STATES PATENTS 1,823,229 Balbaud Sept. 15, 1931 2,291,430 Ingersoll July 28, 1942 2,417,666 Socin Mar. 18, 1947 2,689,564 Adams et al Sept. 21, 1954 

1. IN A PIANO ACTION, THE COMBINATION COMPRISING: A MANUALLY OPERABLE KEY LEVER FULCRUMED INTERMEDIATE ITS ENDS; AN ENDWISE RECIPROCABLE LINK; A CONNECTING ELEMENT ON SAID LINK ADJACENT THE REAR END OF SAID KEY LEVER RESTRAINED AGAINST LONGITUDINAL MOVEMENT RELATIVE TO SAID LINK, SAID ELEMENT HAVING A CONSTRICTED PORTION DEFINING AN ENDLESS CIRCUMFERENTIAL GROOVE DISPOSED TRANSVERSELY OF SAID LINK; A FORK RIGID WITH AND PROJECTING FROM THE REAR END OF SAID KEY LEVER, SAID FORK INCLUDING GENERALLY PARALLEL DISPOSED ARMS HAVING STRAIGHT CONFRONTING EDGES SPACED APART TO PASS THE CONSTRICTED PORTION OF SAID ELEMENT FREELY; AND BARB MEANS ON SAID ARMS AGGRESSIVELY ENGAGING THE SIDEWALLS OF SAID GROOVE. 